Kinetic and thermodynamic properties of several water soluble metalloporphyrins of the meso-substituted vareity are being studied. In particular, we are working with the cobalt, nickel, copper and zinc derivatives of tetr (N-methyltetrapyridyl) prophine and tetracarboxyphenylporphine. We are investigating ligation reactions, redox reactions and aggregation of these species using a variety of kinetic techniques, both classical and relaxation.